I tried to swap the old handguard from my akm with an rail one and this wasnt possible, i have to say that i already had a mosin on my back, then i put it (akm) on the ground, didnt work either, i took the akm back in my hand and then swaped the whole akm (with all worn or pristine add ons) with the handguard on the ground, now i had the handguard in my hands and the akm was gone, buhuhuhu. So i walked around found an ak su and had the same problems, there i even wasnt able to remove the handguard at all and the same a few minutes later with an ak74